How the required score is calculated
A course grade is a weighted average of every graded component. If the final exam is worth a known share of the course grade, the required score solves this equation for the unknown final-exam score: target % = current % × (1 − weight) + final % × weight.
Rearranged for the final exam score, the calculator uses: required final % = (target % − current % × (1 − weight)) ÷ weight, where weight is the final's share of the grade written as a decimal.
Worked example
A student has an 85% going into a final exam worth 20% of the course grade and wants to finish with a 90%. Required score = (90 − 85 × 0.8) ÷ 0.2 = (90 − 68) ÷ 0.2 = 110%. Because that is above 100%, a 90% final course grade is not reachable through the final exam alone — the student would need extra credit or a stronger grade in another component.
Why the final exam's weight matters so much
A final exam worth 10% of the grade can only move the overall percentage by 10 points at most, even with a perfect score. A final worth 40% can swing the final grade dramatically in either direction. Always confirm the exact weight in the syllabus before relying on the result.
When the calculator shows a negative or very low required score
A required score at or below 0% means the target grade is already guaranteed — any score on the final, including a zero, keeps the course average at or above the target. This is common late in a course when strong prior grades have already secured a target letter grade.